Today I’m hiking from Thur Mountain to the Cavan Burren along lanes and among prehistoric relics. This is north-west Ireland, not far from the sea but far enough for me to call it midlands. My route goes from Co Leitrim into Co Cavan, staying close to the border with Northern Ireland. For so long associated with violence and up against the appeal of the west coast, Ireland’s borderland has been ignored by travellers. Yet its history is fascinating and there are many beautiful stretches. Word is starting to get out, but this still feels like Ireland’s undiscovered region.

I spent last night in a B&B in Glenfarne, a thinly spread community of farms and homes. Clancy’s (doubles from €89 B&B, walking packages available) appears to be the area’s heart, a string of businesses along the roadside, under one roof. It’s a B&B, a cafe, a shop and a post office.

“It keeps me out of trouble,” says Jim Clancy, taking a room booking from behind one counter then going to sell stamps from behind another. Breakfast includes boxty, a kind of Irish pancake made of grated potato. While eating, I study my Ordnance Survey map. There are many red labels, indicating sites of archaeological interest. Standing stones are marked only metres behind Clancy’s, territorial markers that could have been erected over 5,000 years ago. Ireland’s boundaries often have a deep history, and there are plenty of standing stones near the border. I ask Jim about them. “We used to play around those stones when we were children,” he says, “but they’re fallen over now and covered in bracken.”

In Grandpa’s footsteps on the shores of Carlingford Lough, Ireland

Read more

This is the problem with OS red labels: some are simply handed down from older maps. A lot can happen to a stone in 100 years, so it is best to get local knowledge. I go to look at the site anyway, and discover a more recent relic. On the platform of a disused railway station is a customs hut, left over from before the European single market. A sign on the door says, Customs and Excise. It is a single-room, corrugated-iron structure, freshly painted and perfectly maintained. It looks like it could be returned to service quite easily.

Thur Mountain (442 metres) is not high but its peak has a certain rugged nobility, especially coated in snow this January morning. When I awoke it was to songbirds perched along Clancy’s back wall but 100 metres up there is only the call of crows. Higher again, and the crows are replaced by tiny pipits, flushed from the heather by my approach. The ling heather will flower in the summer and this land will be purple. Now it is copper-coloured and patched with snow. I look across Glenfarne. The valley fields are mostly brown but here and there a well-loved patch is snooker-table green.

The best affordable hotels, B&Bs and hostels in Ireland

Read more

Among fir trees I seek, but fail to find, the subject of another red label: a sweat house, a sort of primitive sauna. I am determined to find one of these traditional structures, so I head for Moneygashel, where I’m told there’s a good example. Twice, people stop on the lane to offer me a lift. An old man takes me further than he was going as he is enjoying the drive. “My first time out in a week,” he says. “The snow was so thick I couldn’t get down the mountain. Well, I could’ve got down but I wouldn’t have got back up again.”

Moneygashel’s sweat house is indeed in fine condition: about two metres tall, mortarless, built of corbelled slabs. These structures are often beehive-shaped, like this one, with a tiny entrance. Today, ferns have grown around the entrance and in the shadowy interior. The origins of sweat houses are mysterious but they were still used into the 20th century. Originally, the chamber was heated by fire for a day then the naked “sweaters” would crawl inside, blocking the entrance behind them. It was a treatment for rheumatism. This one could have held three sweaters, or five if they were particularly friendly. They were often built near streams, Scandinavian style, for a cold dip immediately on exit. They are generally uncommon but, for some reason, there are dozens in this area. It seems this borderland was gripped by the sweating trend during the 19th century. I mention this to Jim. “Yes, there are loads around here,” he says. “You’d be tripping over them.”

The Border Interpretative Centre by artist John Byrne. Photograph: John Byrne

A thoughtful local has put up a hand-painted sign so I can’t miss the sweat house. The sign itself is a pleasing find. Until recently, such signs were often the limit of tourist infrastructure on Ireland’s borderlands. A fear of violence and crime means some people wouldn’t even approach the border, never mind cross it. The idea of a tourist visiting it would have been a joke. In fact, the artist John Byrne had fun with the idea in 2000, installing what he called The Border Interpretative Centre in a shed by a border road. He printed his own postcards, showing military watchtowers that were still active at the time.

Today, visiting the border is no longer just for comedians and artists. Others are coming and the change can be seen most clearly seen on Cavan Burren, a plateau loaded with prehistoric relics, including some of the finest megalithic tombs anywhere in Ireland. One, Giant’s Grave, is nearly eight metres long, composed of one-tonne slabs arranged to align with the setting sun. I wrote about it for a book about the border, remarking on how little-known it was, despite its extraordinary treasures: “If the borderline did not run over this plateau, there would be tour buses parked here, a shop and a visitors’ centre.”

Now there is a visitors’ centre, albeit a basic one, and it’s unstaffed. Bitumen paths link the tombs and there are information signs every 20 metres. All this is new, but the most striking change is that its trees have been cut away. Last time I visited, the woods were so thick I felt I was walking through tunnels between the relics, each with its own leafy glade. Now everything is exposed. This is more true to how the area would have appeared 5,000 years ago: the whole idea was that these mighty works were visible for miles around. Felling the trees has also revealed what seem to be alignments in the location of tombs. Some suggest that two were built also to align with a cairn on 665-metre Cuilcagh mountain, five miles away.

Cottage with class: a short break on Ireland’s Donegal coast

Read more

Today I also see things I previously missed. A tomb called the Calf House is the size of a garden shed although half-fallen, a great slab of stone sitting at 45 degrees. The original tomb dates back to about 4,000BC, but at some point – a century or so ago – a wall was built into it, converting it into a calf shelter. The information panel delivers these facts dispassionately but I am startled by the continuum. These stones were put up millennia ago, and 200 generations later, a farmer saw fit to add to them. The sacred is mundane; the mundane is sacred.

This says something about this whole valley of red-label relics. The first thing to do is keep expectations in check. These are not all vast constructions and they are not all considered holy; sometimes you can’t even find them. If they were lumped all together, and the human hours they took, there would be something to rival a Mayan pyramid. But they are not lumped together, they are scattered. In fact, they are everywhere. Tombs, cairns, standing stones and sweat houses, seek them around the back of bungalows or in the undergrowth. They might be employed as a child’s den or absorbed into a fence. You might trip over them. This is a place, a people, living with ancient relics as if they were nothing special at all. And I think that is very special indeed. •The Rule of the Land: Walking Ireland’s Border by Garrett Carr is published by Faber & Faber (£13.99). To order a copy for £11.89, go to theguardianbookshop

THREE MORE BORDER HIKESRing of Gullion

South Armagh’s border is still associated with the Troubles but new marked routes are encouraging hikers to explore its beautiful hill country. The major climb is the heart of the ring, Slieve Gullion. Dotted around are bits of twisted steel or cable, the remains of military watchtowers. As one walkers’ website puts it: “Many of our panoramic viewpoints are highly recommended by British military intelligence.”

Cuilcagh mountain

Lough MacNean with Cuilcagh mountains in the background. Photograph: National Geographic Image Collec/Alamy

Ireland’s border goes up and along the entire length of this flat-topped mountain, its highest point. Approach it from the north and there’s a wooden walkway installed to protect the bogland habitat surrounding Cuilcagh. There are ripples in the ground, the remains of “lazy beds” where potatoes were cultivated. Recently, a controversial stairway has been added, going right to the summit. I am not a fan, but it’s good that more people can visit the top. Carry a stone to the peak’s cairn, joining a tradition that is a thousand years old.

Barnesmore Bog

For a frontier with a big sky and not another soul, head to the upland bogs. Barnesmore on the Donegal border should do the trick, a massive area of upland blanket bog, without much turf cutting or farming. There are a few wind turbines, but their service track is useful. Walkers should let somebody know where they are going and be prepared for changes in the weather. Spot large native Irish hare and peregrine falcons that nest on the cliffs.